Referring to FIG. 1, in a conventional video printer, a composite video signal CVS is fed to a Y/C separator B1 and is separated into luminance and color signals Y and C. A switch B2 selects between the separated Y/C signal and a superimposed video signal SVS. The Y/C signal selected by switch B2 is converted into color difference signals R-Y, B-Y and Y by a decoder B3. When a memory B6 is selected by a user using a switch B4, the color difference signals are stored in memory B6 via a line L2. During read out, the color difference signals stored in memory B6 are input to a switch B7 via a line L3. When memory B6 is not selected by the operator using switch B4, the color difference signals are directly input to switch B7 via a line L1. A decoder B8 connected to the output of switch B7 separates the color difference signals into R, G and B signals The R, G, and B signals are input to an encoder B9 and a switch B13.
Switch B13 sequentially selects the input signals according to a R, G, B printing sequence. The selected signals are converted to digital video signals by an analog-to-digital (A/D) converter B12 for storage in a line memory B14. The data stored in line memory B14 is pulse-width-converted by a thermal print head (TPH) controller B15, and the data operates a TPH B16 which performs a color printing. Yellow, magenta and cyan (Y, M, and C) colors are sequentially printed during the color image printing operation.
Meanwhile, the signals fed to encoder B9 are converted into a composite video signal. In response to the output of a monostable multivibrator B11, a switch B10 selects the output from line L4 in a no-printing portion and a video signal having a pedestal level in a printing portion so that a picture has the no-printing portion and printing portion on a monitor connected to an output terminal VSO.
A black bar is produced in the printing portion from left to right, or from right to left, so as to indicate how much of the printing has been carried out.
In the conventional video printer, during a yellow printing, the printer processing status is indicated by the black bar on the screen, while the whole picture to be printed is displayed on the remaining part of the screen. However, magenta and cyan are also printed and displayed in the same way. Therefore, it is impossible to know which color is currently being printed.
Furthermore, during printing, if the user switches the display of the monitor to view another video image, it is also impossible to know how much of the printing has been performed.